stabb



. Gsheets-sheen 1. E. T. STARR.

DENTAL ENGINE.

No. 276,299. Patented Apr. 24, 1883.

N. Finns. Phoxmhqgnpher. washingwn. n. c.

e sheets-sheets. E. T. STARR.

` DENTAL ENGINE. No. 276,299.

Patented Ap1-.24,1883.

WHWESSES INVENTOR Ezafzw,

By 'his .Attorneys N. ETEHS. Phulmlwgnphef, wnhin an.

. Fig' 6 Sheets-Sheet 3.

E. T. STARR.

DENTAL ENGINE.

Patenteg,p1-. 2g), 1883.

` By his Attorneys N. PETKRS. Pnaimmgnpher, wnsnmglon. D. C.

6 Sheets-Sheet 4. E. T. STARR.`

DENTAL ENGINE.

No. 276,299. Patented Ap1.24,1888.

[NVEJV'TR Ell: 1715725019.

By his Attorneys e sheets-sheen 5.V

E. T. STARR.m

DENTAL ENGINE.

Patented Apr. 24, 1883i di INVEJV'TR Ell; TLV/curr TVI'IN'ESSES Y@ L Q4@ yf W @2W/7 By his ./lttornezjs' 6 Sheets--Sheet 6.

E, TSTRR.

DENTAL ENGINE.

' By his .dttorneys UNITED STATES "PATENT @PEICEO ELI rr. STARR, oF PHILADELPHIA, PENNSYLVANIA, AssIGNon To SAMUEL S. WHITE, oF SAME PLACE,

DENTALENGINE.

SPECIFICATION forming part of Letters' Patent No. 276,299, dated April 24, 1883,

Application filed June 27, 1879. Patented in England yAugust 13, 1879, No. 3,262.

To all whom tt may concer-n.-

Be it known that I, ELI T. STARR, of the city and county of^Philadelphia-, in the State of Pennsylvania, have invented certain new and useful Improvements in Dental Engines,

of which the following is a specification.

Myinvention relates more especially to dental engines ot the class comprising in their struct- -nre a hase or stand carrying a foot-treadle to and drivingpulley, an arm or frame rising from the base, a driven pulley connected with the upper end ot' the engine-arm, a belt-connection betweenthe driving and driven pulleys, i and a liexible power-conveyer receiving motion t5 from the driven pulley and imparting motion to the operating-tool mounted in a handle or` hand-piece, the hand-piece being free to bel moved about in various directions to operatey at different points in the patients mouth.

great freedom of movement to the hand-piece and operating-tool carried thereby, and also to the liexible power-conveyer or shaft relatively to the engine-arm without interrupting, 2 5 the transmission of the driving-power, which` ends I attain by means of certain new combi4 nations of devices, which will hereinafter be specifically designated, and then pointed out.`

at the close of the specication. In lthe accompanying drawings, which show my im provement-s as embodied inthe best way `now known to me,Figure lis a plan ortop view of the improved engine-head; Fig. 2, a side view thereof, showing the upper works of the engine, including the flexible power-conveyer and hand-piece, the latter being partly in section; Fig. 3, a side view, partly in section,

showing the head as rocked to a position dit'- ferent from that shown in Fig. 2; Fig. 4, a

.4o longitudinal vertical section through the ap The object of my present invention is to give thereof, the rocking engine-head being in a different position from that shown in Fig. 8 and the flexible power-conveyer broken away; Fig. l0, a longitudinal central section through the modified l'orm of apparatus on the line 3 3 of Fig. 11; Fig. 1l, a plan or top view there of; Fig. l2, a vertical section therethrough ou the line 5 5 of Fig. 11; and Fig. 13, a view of the apparatus similar to that showniu Fig. 8, 6o but with the envelopingsheath or cover for the iiexible shaft or power-conveyer omitted.

The base,the standard rising therefronI,the treadle, and the lower parts of the engine, as shown in Figs. 6 and 7, together with the 65 rocking engine-arm A, are shown as of an inI- proved form of"construction and organization, not necessary-to be here described with minuteness or in detail, as the invention embodied therein and thereby is fully sho\vn,de 7o scribed, and claimed by me in an application for Letters Patent of the United States tiled February l, 1879, and, moreover, such detail description is not necessary to a proper understanding ot' the suhiect-matter claimed herein, 7 5 the said parts being illustrated with the object `Inore especially of showing my present improvements as embodied and organized in a complete dentalengine ready for use.

rlhe engiuearm A,which may be connected 8o with the standard rigidly, or so as to rock to and fro, is shown as tubular forthe reception Vof the pivotal shank, journal, or spindle B of the engine-head or lateral arm, so that said head may turn or swivel freely horizontally around or upon the engine-arm, as usual. The upper end of said pivotal shank B is forked, branched, or provided with `a yoke, as clearly shown lin Figs. l, 5, and l2, the upper ends of the arms of the said yoke or fork receiving the 9o pivot-bolt or pivots c of the crosswise pivotal connection which connects the lateral arm or engine-head D with the engine-arm A, with the capacity of rocking or vibrating freely relatively to the engine-arm and to the shank, hereinafter described.

In the form of engine shown in Figs. l to 7, inclusive, the enginehead or lateral arm 1) has the form of a frame provided at its butt with a yoke, 0, whose branches areconnected roo with the pivots c, before mentioned, and this arm carries in` suitable bearings a shaft or spindle, E, said shaft having a pulley, F, mounted upon it, which constitutes the driven pulley of the engine, and imparts the required rotary motion to the said spindle when driven by the belt-connection running from the driving-pulley, hereinafter fully described. The outer end of this driven spindle or shaft E is socketed preferably for the reception of the inner end of the iiexible power conveyer or shaft G, said inner end of the conveyer being inserted in the socket and secured therein. The driven spindle and tleXible shaft are shown as'secured together by a clamp, the walls of the socket being split, so as to form spring clamping-jaws,

which are compressed upon the flexible shaft` or its inner stift' section, g, by means of a screwnut, G', which works upon suitable threads formed upon the inclined or tapering circumference of the walls of said socket, as clearly illustrated in the drawings.

The iiexible power-conveyer, which preferably consists of a coiled-wire shaft such as are in common use, is connected at its outer or free end with. a suitable chuck, mandrel, or tool-holder, K, ot' any suitable construction, soas to turn it, said tool-holder being mounted in suitable bearings in a hand-piece casing, J, and being also adapted for the ready interchange of the operating-tools used with this classofenginesinperformingdentaloperations.

In the form of apparatus shown in Figs. S to 13, inclusive, the engine-head or lateral arm has the form of a tube, D, fitted at its butt with a yoke, G, forming a part ofthe rocking pivotal connection with the engine-arm A; although in this form of engine, as well as the form iirst described, the members of the pivotal connection which are connected by the pivot or pivots need not necessarily be of yoke form. AThis tubular lateral arm or engine-head D forms a bearing for the tubular journal E, the driven pulley F of the engine being firmly mounted upon or forming part of the said journal, which is locked from endwise movement in the bearing D by means of a circumferential groove, e, in which the end of a screw, cin this instancelits after passing through said bearing D, as clearly shown in Fig. 10.

The inner end of the iieXiblepower-conveyer G is preferably secured to the tubular journal E by means of its stiff section g, which is passed through the journal and clamped by a suitable nut, H, which works upon threads formed upon the tapering circumference ofthe split rear end of the tubular journal, as clearly shown.

The tubularlateral armD has loosely mounted upon its end a telescoping ferrule, ring, or

portion, D', secured or firmly connected to the inner end of the flexible sheath or cover I, such as those in common use, which envelops and protects the iexible power-conveyer. At the outer or free end of the iieXible sheath is secured the hand-piece casing J, as clearly shown in-Fig. 8, while the enveloped powerconveyer is connected with the butt-end of the tool-holder mounted in said hand-piece casing to turn it, as before stated. The object of the loose cylindrical telescopic connection D between the hand-piece casing and the enginehead or lateral arm is to permit of slight endwise movement of the sheath relatively to the shaft during the eXure or bending of the shaft and sheath at work, whereby breakage, cramping, or straining of either the shaft or sheath is prevented. The tool-holder or spindle of the hand-piece is prevented from moving endwise in its bearings in the hand-piece casing as usual, and were the hand-piece casing connected rigidly with the engine-head by means of the enveloping-sleeve I, there would be great danger of straining and breaking the shaft or sheath, because during. the iexure of the shaft and sheath in use one bends to a greater extent than the other; and to compensate this there should be arcapability of slight endwise play of the sheath upon the shaft. This I attain by interposing between the handpiece casing and the en gine-head or lateral arm a loose telescopic joint, which, while it enables the hand-piece to be turned upon the spindle tool-holder to conform to the turning movements of the hand of the operator, also permits slightendwise play of the sheath, to avoid breakage or cramping and binding in the use of the engine.

In some instances I contemplate dispensing with the flexible sheath or cover for the power-conveyer in the form of head shown in Figs. 8 to '13, inclusive, in order to give more exibility or freedom of movement to said powerconveyer, Fig. 13 showing the apparatus with the sheath removed.

The driving-belt L passes fromthe drivingpulley, at the lower end of the engine-arm, around the driven pulley F, which pulley, it will be observed, is mounted upon the spindle or shaft, or upon its journal E, carried by the engine-head or lateral arm, in such manner as to swing, vibrate, or rock around the pivots or pivot-bolt c as a center, the pivots or ends ot' the pivot-bolt projecting beyond the arms of the yoke or fork of the shank B, being provided with small guide-pulleys b b for the driving-belt, when the engine-head is rocked to a IOO IIS

position requiring their aid, as in Figs. 3 and 9 5 or the said guide-pulleys may be mounted on independent pivots, if desired.

In order that the tension of the driving-belt may not be materially changed by the variation of position of the engine-head or lateral arm and pulley carried thereby when that head is rocked or turned, I preferably secure upon the upper end of the engine-arm A a collar or annular shoulder, M, fastened by asetscrew, m, and interpose between said collar and the annular shoulder or portion M, near the upper end of the turning shank B, next its yoke, a spiral spring, N, which tends to cause the shank B of the engine-head to slide endwise in the engine-arm. This shank-spring, it will be obvious, operates upon the en gine-head and the driven pulley carried by itwitli a yieldingpressure, and preserves the requisite IZO tension of the drivin g-belt connection i`nall the movements of said h'ead.

In both of theabove-described forms of engine it will be noticed that the driven pulley F is arranged tooverhang the pivot c of the rocking pivotal connection of the engine-head or lateral arm D, the said pulley being at the side of said pivot opposite that at whichthe arm extends, and the belt-connection L, when in place, practically prevents the said pulley from rising, while the spring N, operating through the pivot c, tends to force the lateral arm upward. As this upward pressure is exerted between the driven pulley and the larger portion of the lateral arm, the shankspringexerting it counterbalances in wholeorin part the downward pressure due to the weight of the lateral arm and its appurtenances, and causes it to standout laterally from the engine-arm. r

It will be obvious that the collar M `may be reversed, as shown in Figs. 8, 9, 10, 12, and l3that is, the` said collar may be secured upon the upper end of the turning sliding shank B, and the spring interposed between said collar and the top of the engine-arm in which the shank works; or the shank B may be tubular, andthe spring may be inserted within it;

or the spring may be inserted in a tubular cavity in the` engine-arm A, and may operate against the end of the shank B. Y

From the foregoing description it will be obvious that the hand-piece is given great freedom ot' movement not only by the iiexure of the flexible power-conveyer, but by the universal engine-head or lateral arm, which possesses the capacity of turning or swiveling horizontallyand ot' rocking vertically, while at the same time the proper tension ofthe belt is maintained and the weight of'the rocking head is counterbalanced by the action ot' the shank-spring. The rocking arm or head and its appurtenances, when not in use, may also4 be rocked downward, so that the flexible power-conveyer will hang vertically and straight at one side of the engine-arm, which position tends to prevent it from taking a set in` a curved direction. y

I am aware that rocking and turning or universa] engine-heads are very common, and do not broadly claim such a device, limiting myselfv to the combinations ot' devices set out specifically in my claims.

I do not wish to be understood as claiming herein, first, the combination of the lateral larm, the rocking pivot thereof, the shank `of said arm, the shank-spring, the engine-arm, and the overhanging driven pulley carried by said lateral arm; nor, secondly, the combination of the lateral arm,the rocking pivot thereof, the pivotal shank of said arm, the shankspring, the engine-arm, the overhangingdriven pulley carried by said lateral arm, and` the tiexible power-conveyer driven by said pulley. These two recited combinations are claimed in and form partof the subject-matter of my application for Letters Patent of the United States` filed subsequently to the present one-- .before` set forth,with an engine arm or support, `of the lateral arm, the rocking -pivot crosswise of said arm, the driven pulley overhanging said pivot at the side thereof opposite that at which the lateral arm extends, and the exible power-conveyer driven by said pulley.

3. The combination, substantially as hereinbefore set forth, of the lateral arm, the rocking pivot of said arm, the driven pulleyoverhanging said pivot, as before described, and y the shank of said lateral arm, with which itis connected by the rocking pivot, said shank forming a connection between said lateral arm and an engine arm or support. t

4. The combination, substantially as hereinbefore set forth, with an engine arm or support, ot' the lateral arm, the rocking pivot ot" said arm, the driven pulley overhanging said pivot, as before described, the shank of said lateral arm, with which it is connected by the rockin g pivot, the exible power-conveyer, and the hand-piece. A

5. The combination, substantially as hereinbetore set forth, of an enginehead, a ilexible driving-shaft connected therewith, a. flexible sheath enveloping said shaft, and ya Vhandpiece casing connected with said engine-head by `means of a loose telescopic joint and said flexible sheath, whereby the sheath may have slight end-play relatively to the drivin g-shait which it envelops and protects.

6. The combination, substantially as hereinbefore set forth, of the engine-head, the flexible driving-shaft, the enveloping-sheath of said shaft, the tool-holder connected withthe outer end of said shaft, and the hand -piece casing, in which said tool-holder has its bearings, connected with said engine-'head by means of the loose cylindrical telescopic joint and said sheath, whereby the band-piece casing may turn upon the tool-holder to conform to the turning movements of the hand ot' the operator, while the sheath may have slight end-"play relatively to the flexible drivingshaft. y. In testimony whereof I have hereunto subscribed my name. l y

` ELI IKST-ARR.

Witnesses: y

,WivL J. PEYTON, l GIBBEs M. MAYNADIER. 

